[Federal Register Volume 59, Number 29 (Friday, February 11, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-1584]


[[Page Unknown]]

[Federal Register: February 11, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-NM-08-AD; Amendment 39-8807; AD 94-03-01]

 

Airworthiness Directives; McDonnell Douglas Model DC-9 Series 
Airplanes and C-9 (Military) Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to McDonnell Douglas Model DC-9 series airplanes and 
C-9 (military) airplanes, that currently requires the implementation of 
a program of structural inspections to detect and correct fatigue 
cracking in order to ensure the continued airworthiness of these 
airplanes as they approach the manufacturer's original fatigue design 
life goal. This amendment requires, among other things, revision of the 
existing program to require visual inspections of additional structure. 
This amendment is prompted by new data submitted by the manufacturer 
indicating that certain revisions to the program are necessary in order 
to increase the confidence level of the statistical program to ensure 
timely detection of cracks in various airplane structures. The actions 
specified by this AD are intended to prevent fatigue cracking that 
could compromise the structural integrity of these airplanes.

DATES: Effective on March 14, 1994.
    The incorporation by reference of certain publications listed in 
the regulations was approved previously by the Director of the Federal 
Register as of November 21, 1988 (53 FR 46866).
    The incorporation by reference of certain other publications listed 
in the regulations was approved by the Director of the Federal Register 
as of March 14, 1994.

ADDRESSES: The service information referenced in this AD may be 
obtained from McDonnell Douglas Corporation, P.O. Box 1771, Long Beach, 
California 90846-1771, Attention: Business Unit Manager, Technical 
Publications--Technical Administrative Support, C1-L5B. This 
information may be examined at the Federal Aviation Administration 
(FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, 
SW., Renton, Washington; or at the FAA, Transport Airplane Directorate, 
Los Angeles Aircraft Certification Office, 3229 East Spring Street, 
Long Beach, California; or at the Office of the Federal Register, 800 
North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: David Hsu, Aerospace Engineer, 
Airframe Branch, ANM-122L, FAA, Transport Airplane Directorate, Los 
Angeles Aircraft Certification Office, 3229 East Spring Street, Long 
Beach, California 90806-2425; telephone (310) 988-5323; fax (310) 988-
5210.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations by superseding AD 87-14-07 R1, Amendment 39-6019 
(53 FR 46866, November 21, 1988), which is applicable to McDonnell 
Douglas Model DC-9 series airplanes and C-9 (military) airplanes, was 
published in the Federal Register on March 29, 1993 (58 FR 16505). The 
action proposed to require, among other things, revision of the 
existing Structural Inspection Document (SID) sampling program to 
require additional visual inspections of all Principal Structural 
Elements (PSE) on certain airplanes.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    One commenter supports the proposal.
    Several commenters objected to the proposed repair requirements 
which would require that any cracked structure detected during the 
required inspections be repaired ``in accordance with a method approved 
by the Manager of the Los Angeles Aircraft Certification Office 
(LAACO).'' These commenters prefer the language of AD 87-14-07 R1, 
which permitted cracked structure to be repaired ``in accordance with 
an FAA-approved method,'' and request that the rule be revised to 
include this language. This requested language would allow repairs to 
be approved routinely by the manufacturer, Designated Engineering 
Representatives (DER), or SFAR 36-authorized organizations, without 
prior approval by the Manager of LAACO. The commenters' justification 
for this request involves three points:
    1. The commenters contend that it is not logical that the manner of 
repair approval should differ between repairs of PSE's found cracked 
during a SID inspection and repairs of PSE's found cracked during 
inspections other than those directly called for by the SID program.
    2. The commenters also contend that it should not be necessary to 
involve the Manager of the LAACO in the repair approval process, since 
the process takes too much time. The commenters consider that adequate 
repair procedures already are available in the DC-9 Structural Repair 
Manual (SRM) and the service bulletins referenced in the SID; repair 
procedures can also be designed and approved by DER's without further 
review and approval of the LAACO.
    3. Several of the commenters also request that the airplane 
manufacturer, operator DER's, and SFAR 36-authorized operators be 
allowed to approve repairs that are outside the scope of the SRM, at 
least temporarily, in order to allow the airplane to be returned to 
revenue service pending the outcome of a subsequent damage tolerance 
assessment (DTA) of the repair, which is required by the SID program of 
all repairs. These commenters state that restricting approval of such 
repairs to the LAACO Manager would hamper repair efforts and ``would 
have an appreciable effect on the airplane's return-to-service times.''
    The FAA does not concur with the commenters' requests. While it is 
true that DER's and SFAR 36-authorized organizations are authorized to 
approve certain repairs of cracking that is found during routine 
maintenance or opportunity inspections, the FAA considers that any 
cracking detected in PSE structure during an inspection required by 
this AD (and the SID program) is indication of an airworthiness concern 
of a complex nature. Such cracking does not warrant ``routine'' 
handling, but requires expeditious action and a special approach to 
address it. It is crucial that the FAA be aware of all repairs made to 
PSE's or to their configuration. Where repair data do not exist, it is 
essential that the FAA have feedback as to the type of repairs being 
made. Given that possible new relevant issues might be revealed during 
this process, it is imperative that the FAA have such feedback. Only by 
reviewing repair approvals can the FAA be assured of this feedback and 
of the adequacy of the repair methods. The FAA has determined that 
standardization and continuity of repair approvals can best be 
maintained by having one single point of approval for all repairs of 
cracks in PSE's identified during SID inspections required by this AD. 
Since the Manager of the LAACO is accountable for the primary oversight 
for the actions regarding this AD, it is appropriate that he be this 
single point of approval. His involvement, therefore, is warranted in 
the development and approval of repairs.
    Standardization and continuity of repair approval is especially 
important in light of the complexity of the DC-9 SID program. This 
program is unique in that it is based on the principle of statistical 
sampling, which requires cooperation between aircraft operators, the 
manufacturer, and the FAA in selecting airplane samples, accomplishing 
inspections, reporting discrepancies as they are found, and evaluating 
the safety impact of the discrepancies so that timely program 
adjustments can be made and the appropriate corrective actions taken to 
protect both the discrepant airplane and the fleet. For example, when 
one bona fide fatigue crack is determined, the inspection and repair 
requirements must be developed in a timely manner to protect the entire 
Model DC-9 fleet. This requires coordination with the Manager of the 
LAACO for the review of all SID findings and a timely determination of 
bona fide fatigue cracking.
    Further, cracked PSE structure detected during an inspection that 
is not directly required by the SID must first be reported to the FAA 
by the operator via a Service Difficulty Report (SDR), as is required 
by the relevant operating rules of the Federal Aviation Regulations. 
These SDR reports are compiled in an SDR data base that is used by the 
FAA for trend analysis and data studies used in planning, directing, 
controlling, and evaluating various airworthiness programs. Cracked PSE 
structure found during an inspection called out by the SID program (and 
this AD) are compiled into a SID data base that is used by the FAA for 
many of the same purposes as SDR data base, including identification of 
necessary revisions to the SID program itself. The Manager of the LAACO 
has access to both the SDR and the SID data bases and, therefore, he is 
in a unique position that affords him a broad overview both to 
understand and assess the overall cracking and repair environment, and 
to implement timely initiatives to address and manage it.
    As part of the SID program, every repair of PSE structure is 
required to have a DTA in order to establish its effect on the fatigue 
life of the affected PSE structure. The DTA process involves the review 
and use of type design data that are proprietary and may not be 
available to those persons (such as a DER) who are generally authorized 
to approve routine repairs. For this reason, it is appropriate that the 
Manager of the LAACO be the focal point in the DTA approval process.
    In some cases, repairs are made to PSE structure as a result of 
cracking that was found during an opportunity inspection, and the 
approval of the repair is made without the coordination of the 
manufacturer and the LAACO. When the time arrives for that PSE to be 
inspected in compliance with the AD, the PSE becomes a ``discrepant 
PSE.'' If a DTA were not accomplished on the ``discrepant PSE'' at the 
time of the repair, compliance with the AD could require that the 
repair be removed or modified at a later time. In either case, the 
Manager of the LAACO is asked to ensure that all repairs to cracked 
PSE's comply with the AD.
    The FAA considers that any repair to cracked PSE's without the 
required DTA can only be temporary, and will eventually require 
coordination with the Manager of the LAACO. Most methods of repair 
specified in the DC-9 Structural Repair Manual, the relevant service 
bulletins, or DER-designed repairs do not include a continuing 
inspection program to ensure that the repair is inspected at the same 
level of safety as the original PSE structure. A DTA can be done most 
easily at the time of repair, rather than at a later date when the 
details of the repair may be hard to obtain and, undoubtedly, would be 
more costly. Currently, the Manager and staff of the LAACO are working 
very closely with the manufacturer to expedite interim repair approval 
requests. Such requests may be made under the provisions of paragraph 
(d) of the final rule.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule as proposed.
    There are approximately 920 Model DC-9 series airplanes and C-9 
(military) airplanes of the affected design in the worldwide fleet. The 
FAA estimates that 586 airplanes of U.S. registry and 19 U.S. operators 
would be affected by this proposed AD.
    Incorporation of the SID program into an operator's maintenance 
program, as was required by AD 87-14-07 R1, necessitates approximately 
1,000 work hours (per operator), at an average labor cost of $55 per 
work hour. Based on these figures, the cost to the 19 affected U.S. 
operators to incorporate the SID program, which was required previously 
in accordance with AD 87-14-07 R1, is estimated to be $1,045,000.
    The incorporation of the additional procedures that are required by 
this new AD action will require approximately 62 additional work hours 
per operator to accomplish, at an average labor cost of $55 per work 
hour. Based on these figures, the cost to the 19 affected U.S. 
operators to incorporate these additional procedures into the SID 
program into an operator's maintenance program is estimated to be 
$64,790.
    The recurring inspection costs, as was required by AD 87-14-07 R1 
and continues to be required by this new AD action, is approximately 
341 work hours per airplane per year, at an average labor cost of $55 
per work hour. Based on these figures, these recurring inspection costs 
are estimated to be $18,755 per airplane, or $10,990,430 for the 
affected U.S. fleet.
    The recurring inspection procedures that are added to the program 
by this new AD action will require approximately 21 additional work 
hours per airplane per year to accomplish, at an average labor charge 
of $55 per work hour. Based on these figures, the additional recurring 
inspection cost impact added by this AD on U.S. operators is estimated 
to be $1,155 per airplane, or $676,830 for the affected U.S. fleet.
    Based on the figures discussed above, the total cost impact of this 
AD is estimated to be $11,732,050 for the first year, and $11,667,260 
for each year thereafter. These ``total cost impact'' figures assume 
that no operator has yet accomplished any of the requirements of this 
AD. However, it can be reasonably assumed that a majority of affected 
operators have already initiated the original SID program (as required 
by AD 87-14-07 R1) and many may have already initiated the additional 
inspections required by this new AD action.
    Additionally, the number of required work hours for each inspection 
requirement of this AD (and the SID program), as indicated above, is 
presented as if the accomplishment of those actions were to be 
conducted as ``stand alone'' actions. However, in actual practice, 
these actions for the most part will be accomplished coincidentally or 
in combination with normally scheduled airplane inspections and other 
maintenance program tasks. Therefore, the actual number of necessary 
additional work hours will be minimal in many instances. Further, any 
costs associated with special airplane scheduling can be expected to be 
minimal.
    The regulations adopted herein will not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) will not have a 
significant economic impact, positive or negative, on a substantial 
number of small entities under the criteria of the Regulatory 
Flexibility Act. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 14 CFR part 
39 of the Federal Aviation Regulations as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-6019 (53 FR 
46866, November 21, 1988), and by adding a new airworthiness directive 
(AD), amendment 39-8807, to read as follows:

94-03-01 McDonnell Douglas: Amendment 39-8807. Docket 93-NM-08-AD. 
Supersedes AD 87-14-07 R1, Amendment 39-6019.

    Applicability: Model DC-9-10, -20, -30, -40, -50 series 
airplanes, and C-9 (Military) airplanes; certificated in any 
category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To ensure the continuing structural integrity of these 
airplanes, accomplish the following:
    (a) Within one year after December 23, 1988 (the effective date 
of AD 87-14-07 R1, Amendment 39-6019), incorporate a revision into 
the FAA-approved maintenance inspection program which provides for 
inspection(s) of the Principal Structural Elements (PSE) defined in 
McDonnell Douglas Report No. L26-008, ``DC-9 Supplemental Inspection 
Document (SID),'' Section 2 of Volume I (All Series) of Revision 1, 
dated November 1987, in accordance with Section 2 of Volume III-87, 
dated November 1987, of the SID. The non-destructive inspection 
(NDI) techniques set forth in Section 2 of Volume II, dated November 
1987, of the SID provide acceptable methods for accomplishing the 
inspections required by this paragraph. All inspection results 
(negative or positive) must be reported to McDonnell Douglas, in 
accordance with the instructions contained in Section 2 of Volume 
III-87, dated November 1987, of the SID. Information collection 
requirements contained in this regulation have been approved by the 
Office of Management and Budget (OMB) under the provisions of the 
Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have 
been assigned OMB Control Number 2120-0056.

    Note 1: Volume II, dated November 1987, of the SID is comprised 
of the following: 

------------------------------------------------------------------------
                                                              Revision  
                   Volume designation-                      level shown 
                                                             on volume  
------------------------------------------------------------------------
Volume II-10/20-.........................................  Original.-   
Volume II-20/30-.........................................  1.           
Volume II-40-............................................  Original.-   
Volume II-50-............................................  Original.    
------------------------------------------------------------------------

    -(b) Within 6 months after the effective date of this AD, 
replace the revision of the FAA-approved maintenance inspection 
program required by paragraph (a) of this AD, with a revision that 
provides for inspection(s) of the PSE's defined in McDonnell Douglas 
Report No. L26-008, ``DC-9 Supplemental Inspection Document (SID),'' 
Section 2 of Volume I of Revision 3, dated April 1991, in accordance 
with Section 2 of Volume III-92, dated July 1992, of the SID.
    (1) Visual inspections of all PSE's on airplanes listed in 
Volume III-92, dated July 1992, of the SID planning data, are 
required by the fleet leader-operator sampling (FLOS) program at 
least once during the interval between the start date (SDATE) and 
the end date (EDATE) established for each PSE. These visual 
inspections are defined in Section 3 of Volume II, dated April 1991, 
of the SID, and are required only for those airplanes that have not 
been inspected previously in accordance with Section 2 of Volume II, 
dated April 1991, of the SID.
    (2) The NDI techniques set forth in Section 2 of Volume II, 
dated April 1991, of the SID provide acceptable methods for 
accomplishing the inspections required by this paragraph.
    (3) All inspection results (negative or positive) must be 
reported to McDonnell Douglas, in accordance with the instructions 
contained in section 2 of Volume III-92, dated July 1992, of the 
SID. Information collection requirements contained in this 
regulation have been approved by the OMB under the provisions of the 
Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have 
been assigned OMB Control Number 2120-0056.

    Note 2: Volume II, dated April 1991, of the SID is comprised of 
the following: 

------------------------------------------------------------------------
                                                               Revision 
                    Volume Designation-                      level shown
                                                              on volume 
------------------------------------------------------------------------
Volume II-10/20............................................            3
Volume II-20/30............................................            4
Volume II-40...............................................            3
Volume II-50...............................................            3
------------------------------------------------------------------------

    Note 3: NDI inspections accomplished in accordance with the 
following Volume II of the SID provide acceptable methods for 
accomplishing the inspections required by this paragraph: 

------------------------------------------------------------------------
                                               Revision       Date of   
           Volume Designation--                level--       revision   
------------------------------------------------------------------------
Volume II-10/20-- -.......................  3---.........  April 1991.  
Volume II-10/20-- -.......................  2---.........  April 1990.  
Volume II-10/20---........................  1---.........  June 1989.   
Volume II-10/20--.........................  Original- -..  November     
                                                            1987.       
Volume II-20/30---........................  4---.........  April 1991.  
Volume II-20/30---........................  3---.........  April 1990.  
Volume II-20/30---........................  2---.........  June 1989.   
Volume II-20/30---........................  1---.........  November     
                                                            1987.       
Volume II-40---...........................  3---.........  April 1991.  
Volume II-40---...........................  2---.........  April 1990.  
Volume II-40--............................  1---.........  June 1989.   
Volume II-40---...........................  Original-....  November     
                                                            1987.       
Volume II-50---...........................  3---.........  April 1991.  
Volume II-50---...........................  2---.........  April 1990.  
Volume II-50---...........................  1---.........  June 1989.   
Volume II-50---...........................  Original--...  November     
                                                            1987.       
------------------------------------------------------------------------

    (c) Any cracked structure detected during the inspections 
required by paragraph (a) or (b) of this AD must be repaired before 
further flight, in accordance with a method approved by the Manager, 
Los Angeles Aircraft Certification Office (ACO), FAA, Transport 
Airplane Directorate.

    -Note 4: Requests for approval of any PSE repair that would 
affect the FAA-approved maintenance inspection program that is 
required by this AD should include a damage tolerance assessment for 
that PSE.

     -(d) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Los Angeles ACO, FAA, Transport 
Airplane Directorate. Operators shall submit their requests through 
an appropriate FAA Principal Maintenance Inspector, who may add 
comments and then send it to the Manager, Los Angeles ACO.

     -Note 5: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

     -(e) Special flight permits may be issued in accordance with 
FAR 21.197 and 21.199 to operate the airplane to a location where 
the requirements of this AD can be accomplished.
    (f) Certain of the inspections to be added to the FAA-approved 
maintenance program shall be done in accordance with McDonnell 
Douglas Report No. L26-008, ``DC-9 Supplemental Inspection Document 
(SID),'' dated November 1987. The incorporation by reference of this 
document was approved previously by the Director of the Federal 
Register, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51, as 
of December 23, 1988 (53 FR 46866, November 21, 1988). Certain other 
of the inspections to be added to the FAA-approved maintenance 
program shall be done in accordance with the following volumes of 
McDonnell Douglas Report No. L26-008, ``DC-9 Supplemental Inspection 
Document (SID),'' that contain the lists of effective pages 
indicated below:---------

--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                           Revision                     
             Document                                                  Page number                                          level             Date      
--------------------------------------------------------------------------------------------------------------------------------------------------------
Volume I--All Series.............  List of Effective Pages A, B, C....................................................  3............  April 1991.      
Volume II-10/20..................  List of Effective Pages A, B, C, D, E, F, G, H, I, J, K............................  3............  April 1991.      
                                   L..................................................................................  2............  April 1990.      
Volume II-20/30..................  List of Effective Pages A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, U.  4............  April 1991.      
                                   T..................................................................................  Original.....  April 1990.      
Volume II-40.....................  List of Effective Pages A, B, C, D, E, F, G, H, I, J, K, L, M, N, O................  3............  April 1991.      
Volume II-50.....................  List of Effective Pages A, B, C, D, E, F, G, H, I, J, K, L, M, N, O................  3............  April 1991.      
Volume III-92 All Series.........  Entire Document....................................................................  Original.....  July 1992.       
--------------------------------------------------------------------------------------------------------------------------------------------------------

    This incorporation by reference was approved by the Director of 
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR 
part 51. Copies may be obtained from McDonnell Douglas Corporation, 
P.O. Box 1771, Long Beach, California 90846-1771, Attention: 
Business Unit Manager, Technical Publications--Technical 
Administrative Support, C1-L5B. Copies may be inspected at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington; or at the FAA, Transport Airplane Directorate, Los 
Angeles Aircraft Certification Office, 3229 East Spring Street, Long 
Beach, California; or at the Office of the Federal Register, 800 
North Capitol Street, NW., suite 700, Washington, DC.
    (g) This amendment becomes effective on March 14, 1994.

    Issued in Renton, Washington, on January 20, 1994.
Darrell M. Pederson,
 Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-1584 Filed 2-10-94; 8:45 am]
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